Motorized press ram adjusting means



Oct. 24, 1 H. A. HOLBERSON MOTORIZED PRESS RAM ADJUSTING MEANS 3Sheets-Sheet i HENY A. HOL ERSON /2 mai FIG.

1967 H. A. HOLBERSON v MOTORIZED PRESS RAM ADJUSTING MEANS 5Sheets-Sheet 2 Filed Nov. 12, 1963 INVENTOR H E N RY A. HOLBERSON Oct.24, 1967 H. A. HOLBERSON 3,348,405

MOTORIZED PRESS RAM ADJUSTING MEANS 7 Filed Nov. 12, 1963 3 Sheets-Sheet5 FIG. 5.

H E N RY A. HOLBERSON United States Patent This invention relates to theart of forming shapes by drawing or pressing'sheetmaterial'such as sheetsteel in the manufacture of receptacles of various kinds and is morespecifically directed'to'improveinents in a drawing press such as thosenow employed inmaking bathtubs, sinks, fuel tanks and the like.

In drawing or pressing sheets in the manufacture of articles of thischaracter presses capable of delivering great thrust are utilized andwhen the article is to have acavity or depression of considerable depthin relation to the thickness of the sheet or blank from which it is tobe formed it is essential certain edge portions of the blank berestrained in a controlled manner in their movement relative toth'e drawdie while the cavity is being formed, as if the blank edges can move tooreadily toward the die cavity wrinkles may form in the product while ifthey are too firmly restrained operation of the press may overdraw theblank or even fracture it.

'Itis therefore of extreme importance the pressure of the blank holdingmeans, hereinafter called the outer ram, against the blank near itsedges cooperating with the draw die to frictionally restrain it besusceptible of delicate' control and variable' in' increments of a fewthousandths of an inch or less to compensate for differences in blankthickness, its surface hardness, the lubricant used to minimize diefriction and wear, the condition of the die and other factors.- a

It has been the practicein the operation of presses of the charactermentioned to make adjustments of the outer ram manually and by trial anderror methods in accordance with which the pressman on observing that"an adjustment of the ram is needed [for best results signals his wishesto anoperative, or in some instances more than one,- and a manualrepositioning of the appropriate pressure applying collar threaded on areciprocable' plunger is then effected to modify the axial relation ofthe rain to the plungerand hence locally adjust the down position of theram relatively to the subjacent draw die to control the pressure exertedby the ram when a sheet to be drawn is interposed between the ram andthe die.

To maintain an economically high rate of production, the press,producing a drawn article with each stroke of its die, is normallyoperated at several strokes per minute and it is therefore evidentsubstantial production may be lost if the operation of the press isfrequently interrupted to afford opportunity for manual adjustment; onthe other-hand if the press 'is operated for a considerable period whilein need of adjustment many sub-standard and unacceptable articles may beproduced with resultant consignment of excessive amounts of metal toscrap.

It is therefore a principal object of the present invention to providein combination with a draw press comprising a reciprocable die memberand an outer ram surrounding it cooper-able with a complementary femaledie to form from a fiat sheet or blank an article suitable for furtherprocessing to produce a receptacle or the like mean operable from astation apart from the press for incrementally modifying the relationbetween the ram and its actuating mechanism, whereby the pressureexerted locally'by the ram against the blank while disposed on saidcomplementary die can be suitably controlled to frictionally resist to adesired degree transverse movement of correspondingly localized portionsof the blank relatively to ;the ram and die during the formingoperation.

3,348,406 Patented 24, 1967,

Another object is to providemechanical'means forfin' dependentlyactuating threaded collars carried the plungers of a press of thecharacter afores'aid and utilized for applying downwardpressuretotheblan'k holding ram: of the press whereby slippage of theblank,v and-particu the'fortning' ice larly the corners of a rectangularone, during operation may be appropriately controlled; 1

A still further object is to provide a micrometer-like" adjustment forthe pressure applying means associated? with an outer ram in a drawpress "which isself locking save during positive actuation and which canbe disen' gaged when major adjustment is required as when the} dies arechanged o'r'a large difference in the thickness or gage of successivesheets is to be accommodated. V

Yet another object is the provision of'n'o'vel means for effectingadjustments of the character in question which lend themselves to readyinstallation in and association' with existing draw presses comprisingthreaded adjusting plungers without necessitating material orrelativelyexpensive alterations of the" press itself. Other objects,purposes and advant'ag'es'of the inven' tion will hereinafter more fullyappear or will be understood from the following description of one"embodiment of it in association and combination with a draw press of awell known type as more or'les's diagrammatically illus-" trated in theaccompanying drawings in which? FIG. 1 is a front elevation of thepress, witha portion broken away to disclose internal construction,showingin general the relationship of prime 'moversand other mechanismsembodying the invention with respect'to' the" overall structure of thepress as a whole; I 1

FIG. 2 is a horizontal section ontline"2--2 in FIG.

FIG. 3 is an enlarged fragmentaryldetail of FIG.- 2' showing one of thefour substantially identical rah-bad justing elements and associatedmechanisms included} therein; a a 1 1 FIG. 4 is a fragmentaryifrontelevation of the struc'- ture illustrated in FIG. 3; r

FIG. 5 is a diagrammatic representation of electricalcircuits suitablefor energizing the prime movers included in the apparatus and forcontrolling from a a station removed from the press their operationinpredeterrnined increments, and

FIG. 6 is a diagrammatic front view of a control panel such as may beemployed at such station for activating the circuits shown in FIG. 5. s

It may be stated primarily the principal operating ele m-ents andassociated structures of the press as aswhole may be of any specificcharacter, forming'no part of invention, and the latter maybe "utilizedin' associationi with presses specifically dififerent fr-om thatillustrated in; the drawings while the electrical circuits representedFIG. 5 are but typical of circuits which may bedevised for attaining thedesired results. s r, 'V v p Moreover, while the controlsandotherrnechanisms;

associated with but one of the-four prime movers I eIn'-' ploy will behereinafter particularly described his toibe understood those for theothers are identical therewith and" the elements thereof'consequentlyare assigned thesarne reference numerals, being distinguished from, eachother where appropriate by prefix letters A, BC, D designating theseveral units respectively associated with thecorners of theouterram. IV

Thus referring more particularly to the drawings the press in generalcomprises a main frame 1' thejupper part of which affords an enclosurefor the die and rarn open ating mechanisms constituting 'no partfoftheinven'tion; in the drawings these are exemplifiedlby{togglesitrain 2as one of those arranged to actuate'plungersrespectively interconnectedwith the corners of t l1e. .outer. ram 4 the;

I lower face 4 of which is presented by apart may be integral with thesuperjacent body of the ram or separable therefrom as preferred. Theinner or male die is reciprocated by other mechanism (not shown)likewise carried by the main frame and constituting no part of theinvention while the draw die 6, into which inner die 5 propjects a blankB for forming a drawn article, is removably positioned in the lower partof the press frame with its cavity 7 in registry with die 5. It presentsan upper fiat surface 8 on which a blank is disposed when inner dle 5projects a blank B for forming a drawn article, is cooperates torestrain the blank edges while the center portion of the blank is beingforced into die cavity 7 which this surface surrounds. Outer ram 4 issupported from plungers A B C D respectively actuated by a gear toggletrain such as train 2 associated with each in turn actuated from a primemover (not shown).

The several plungers 10 are threaded for a considerable distance fromtheir lower ends and project through sleeves A -D at the corners of theouter ram, a lower threaded collar 12 on each plunger affording supportto the ram from the plunger when the latter is retracted; an upperthreaded collar 15 transmits downward pressure to the outer ram from theplunger while a blank is being formed. As thus far described the pressas a whole is typical of those of the prior art with which mechanismembodying the invention may be associated and combined and thismechanism in such association and combination will now be described withgreater particularity; as the mechanical elements employed for adjustingthe relation between collar 15 and sleeve 11 at each corner of the outerram are identical at the several corners a description of one of them,illustrated in detail in FIGS. 3 and 4, will sufiice for all.

Adjacent the corners of the ram prime movers A B C D preferablyreversible electric motors, are energized and controlled throughsuitable circuits (FIG. 5). Each is connected with a speed reducer 17 ofany appropriate type having on its output shaft 18 a universal joint 19the latter being connected in turn with a shaft 20 carrying a worm gear21. This shaft is journaled in bearings 22, 23 mounted on a block 24which rests on a plate 25 seated on the outer ram and movably securedthereto for adjustment about the vertical axis of the universal jointconveniently by a cap screw 26 which can be entered intO either of twothreaded holes 30, 31 in the plate to hold the block in position tomaintain worm gear 21 in mesh with an annular worm gear 32 on adjacentcollar 15 or retracted to the broken line position indicated in FIG. 3to clear the worm from the gear and permit manual actuation of collar15.

When the plate is in normal position with cap screw 26 entered in holeand worm gear 21 therefore meshing with worm gear 32 operaiton of themotor rotates collar 15 and thereby adjusts its position axially of theram plunger, antifriction thrust bearings 33, 34 restraining the wormgear shaft against axial movement, while a cam 35 on universal joint 19and rotatable with it is disposed to operate a limit switch 36 thefunctions of which will later appear. It may here be noted, however,that this switch as shown in FIG. 5 is connected in the motor controlcircuits in such manner as to interrupt the energizing circuit to theadjacent motor at the completion of one revolution of the worm gearfollowing energization of the motor. Hence, the gear is actuated inincrements and is most advantageously proportioned in relation to thepitch of the cooperative threads on plunger 10 and collar 15 in suchmanner that one revolution of worm gear 21 moves collar 15 axially alongthe plunger but a few thousandths of an inch, preferably about .003". Aswill hereinafter more fully be explained in connection with theelectrical circuits diagrammed in FIG. 5, the motors are energizedindependently from push buttons, arranged together in a movable panel orconsole 40 having a multiple-conductor flexible cable 41 conecting itwith the instrumentalities it controls. Diagrammatically shown in FIG. 6this panel is desirably disposed at a convenient station near the frontor exit side of the press where a pressrnan operating it readily canobserve results produced by the press. Thus for each motor the panelcarries an up push button A -D adapted to energize the correspondingmotor in the direction to return the collar along the plunger in anupward direction, a down push button A -D for lowernig it and a signallight A -D connected to indicate that the respective circuits are inoperation.

Ordinarily after the relation of the outer ram and its four plungers hasbeen adjusted to afford approximately the desired pressure on a blank ofa given thickness when the ram is lowered, lower collars 12 are backedoff to provide a slight clearance of, say, about A" from the lower endof adjacent ram sleeve 11 which of course is taken up when the plungersare raised to lift the ram above the die to permit removal of a formedarticle and introduction of a succeeding blank to the press. As the wormgear drive or collar 15 is self-locking the setting up of the lowercollar against the sleeve to lock the upper one is obviated while withthe lower collar may be asociated a spring actuated latch to prevent itsappreciable turning.

The electrical controls for the several motors as diagrammed in FIG. 5include main leads L L L providing a 3-phase 220-volt power source towhich motors A -D are connected through the contacts of four pole relaysA -D while a v.-a. transformer 51 has its primary winding 52 connectedacross leads L and L to deliver a 100 v.-a. current from its secondarywinding 53 as a power source for the said relays and the signal lights47 47 As the connections more closely related to the respective motorsare identical the following description is to be considered asrepresentative of all of them, those individually identified in FIG. 5with the control elements applicable to operation of motor A beingduplicated in the circuits to the other motors.

More specifically relay 50 has three normally open contacts 61, 62, 63for connecting the motor leads 64, 65, 66 with line leads L L L to drivethe motor in one direction, for example up to raise collar 15, and afourth normally open contact 67 adapted when closed to complete acircuit through the secondary winding of transformer 51, relay solenoid68 and limit switch A which after one revolution of the worm opens andbreaks this circuit; up push button A parallels this limit switch toinitiate operation of the motor while signal light A is connected inparallel with the solenoid and so is lighted concurrently withenergization of the latter to give visible indication the adjustingmeans are functioning.

A down-relay 70 has similar connections with light A but its motorenergizing contacts 71, 72, 73 are connected in motor leads 64, 65, 66to reverse the polarity of the motor and drive it in the oppositedirection and hence to turn collar 15 downward on its plunger when thesecontacts are closed. Limit switch A when the fourth contact 74 of thisrelay is closed is placed in circuit with the relay solenoid 75 andlight A as well, so the light when on indicates the motor circuit isenergized regardless of the direction in which the motor is beingdriven, the terms up and down being used herein as relating respectivelyto operations for decreasing and increasing the pressure of the adjacentcorner of the ram on the blank at the succeeding down stroke of theformer.

Preferably all four pairs of push buttons are located with theirassociated signal lights on panel 40 (FIG. 6), flexible cable 41carrying the several conductors essential to the motor circuits and thepressrnan can therefore readily control the adjustment of all fourcollars selectively and, if desired, concurrently. Thus if he determinescollar A should be raised and collar B lowered he has but to actuatepush buttons A B and the corresponding motors are energized to cause thecollars to be turned in the appropriate directions for one turn each ofthe respective worms 21. If a single increment of adjustment isinsufficient he may again actuate the appropriate button as soon as thelight associated with it is extinguished and can repeat this operationas often as necessary or he may hold the button depressed for as manyrevolutions of the worm as he wishes. Furthermore, if it is found anexcessive travel in one direction has been accomplished it may readilybe compensated by pushing the button reversing the direction ofadjustment to retract the collar or collars a suitable number of turns.

Diagrammatically indicated in dotted lines at 7 in FIG. 2 is the shape,corresponding to the convexity of the inner or male die, of the cavityin a bathtub produced on the press and bounded by an adherent flash,likewise shown in dotted lines F, comprising the peripheral portion ofthe original rectangular blank B from which the tub was drawn anddemonstrating the deformation of the edges of the blank resulting fromthe drawing operation. This flash is normally trimmed off to produce adesired peripheral shape such as one for the flange of the bathtubbefore the drawn article is subjected to further processing to conditionit for the market.

From the foregoing it will be apparent that with the aid of apparatusembodying my invention a pressman stationed at a point apart from thepress but from which he can adequately observe the effects of itsoperation on the successive flat blanks as they are drawn to3-dimensional shape can control with a high degree of precision thepressure exerted by the outer ram upon the blank to clamp it to thesurface of the outer die and thus prevent excess as well as inadequateslippage of the blank relatively to the die during the forming operationand further that when occasion for variation of this pressure arises, asindicated to him by his general knowledge of and experience in the art,he can by appropriate actuation of the various push buttons make thenecessary adjustments in small increments, controlling the pressureexerted on the blank at each corner of the outer ram independently ofthe others and may simultaneously adjust one corner in one direction andone or more of the others in the same or the opposite direction asdeemed appropriate. I have herein suggested such increments mayconveniently be of the order of .003 but it will be obvious that bymodification of the worm and worm gears to change the speed ratiostransmitted or of the limit switches to provide either more or less thana single revolution of the worm each time its actuating motor isenergized larger or smaller increments may be produced.

Hence while I have herein described the invention with considerableparticularity as embodied in the apparatus illustrated in the drawingsit will be understood I do not desire or intend to be limited orconfined thereto or thereby in any way and as changes and modificationsin the form, structure, arrangement and relationship of the parts of themechanical components as well as in the electrical circuits ininstrumentalities included therein will readily occur to those skilledin the art and may be utilized if desired without departing from hespirit and scope of the invention as defined in the appended claims.

Having thus described my invention, I claim and desire to protect byLetters Patent of the United States:

1. In a draw press comprising a vertically disposed frame, a dieproximate the lower end thereof having a cavity and a flat surface aboutthe perimeter thereof, a ram vertically reciprocal in the frame havingan under face cooperative with said surface to clamp a blank thereon, anexternally threaded plunger proximate each corner of the ram and acollar threaded thereon adapted to bear on the adjacent corner of theram, that improvement which comprises a gear on each collar, an elementcooperative therewith to rotate the collar and electrically actuatedmeans for driving said element, a control station apart from the press,and electrical instrumentalities between said station and each saiddriving means selectively operable to actuate each of the latterindependently to thereby move the collars in either direction axially oftheir respective plungers.

2. In a draw press comprising a vertically disposed frame, a dieproximate the lower end thereof having a cavity and a flat surface aboutthe perimeter thereof, a ram vertically reciprocal in the frame havingan under face cooperative with said surface to clamp a blank thereon, anexternally threaded plunger proximate each corner of the ram and acollar threaded thereon adapted to bear on the adjacent corner of theram, that improvement which comprises means for individually rotatingeach collar relatively to the adjacent plunger including an electricmotor, gearing interposed between it and the collar, a control panelremoved from the press, electrical instrumentalities interconnecting thepanel and the motors operable from the panel to selectively actuate themotors in either direction to move any collar axially in eitherdirection and another collar simultaneously in opposite direction.

3. A draw press comprising a die having a cavity and a plane surfaceextending thereabout adapted to support a blank over the cavity, a maledie substantially complementary to the cavity and reciprocal withrespect there to, a substantially rectangular outer ram surrounding themale die, overlying said surface and reciprocal with respect thereto, asleeve carried by the ram adjacent each of its corners, a verticallymovable threaded plunger extending through each sleeve and a pair ofinternally threaded collars on each plunger respectively above and belowthe sleeve, means for reciprocating the plungers, a worm gear on each ofthe upper collars, a worm engageable with each said gear, a reversibleprime mover interconnected with each worm for driving it in eitherdirection, and electrical means operable from a station removed from thepress for selectively and independently energizing said prime movers tothereby modify the axial relation of the plungers and their respectiveupper collars to correspondingly vary the pressure exerted through saidcollars on the sleeves when the ram is resting on a blank disposed onsaid surface.

References Cited UNITED STATES PATENTS 1,774,245 8/1930 Strout 2572,185,096 12/1939 Treer 10058 2,815,709 12/1957 Puhlmann 1002582,889,507 6/1959 Kennedy et a1. 100257 3,030,878 4/1962 Holzer 100257RICHARD J. HERBST, Primary Examiner.

1. IN A DRAW PRESS COMPRISING A VERTICALLY DISPOSED FRAME, A DIEPROXIMATE THE LOWER END THEREOF HAVING A CAVITY AND A FLAT SURFACE ABOUTTHE PERIMETER THEREOF, A RAM VERTICALLY RECIPROCAL IN THE FRAME HAVINGAN UNDER FACE COOPERATIVE WITH SAID SURFACE TO CLAMP A BLANK THEREON, ANEXTERNALLY THREADED PLUNGER PROXIMATE EACH CORNER OF THE RAM AND ACOLLAR THREADED THEREON ADAPTED TO BEAR ON THE ADJACENT CORNER OF THERAM, THAT IMPROVEMENT WHICH COMPRISES A GEAR ON EACH COLLAR, AN ELEMENTCOOPERATIVE THEREWITH TO ROTATE THE COLLAR AND ELECTRICALLY ACTUATEDMEANS FOR DRIVING SAID ELEMENT, A CONTROL STATION APART FROM THE PRESS,AND ELECTRICAL INSTRUMENTALITIES BETWEEN SAID STATION AND EACH SAIDDRIVING MEANS SELECTIVELY OPERABLE TO ACTUATE EACH OF THE LATTERINDEPENDENTLY TO THEREBY MOVE THE COLLARS IN EITHER DIRECTION AXIALLY OFTHEIR RESPECTIVE PLUNGERS.